Vessels, such as ships, produce large amounts of wastewater, such as sewage, galley wastewater, and laundry wastewater. Typically, the wastewater is stored on the vessel or discharged from the vessel with little or no treatment. Storage of the wastewater on vessels requires large holding tanks, which consume valuable floor space in a vessel. In addition, the storage tanks often add undesirable weight to a vessel. Typically, storage tanks are emptied at port facilities and treated in land-based water treatment systems or emptied while the vessel is on the high seas.
The option of discharging wastewater overboard reduces the capacity of storage tanks needed and may, in at least some situations, eliminate the need for wastewater storage tanks altogether. However, discharging raw wastewater into a water body can be extremely damaging. Raw wastewater or wastewater having little treatment often is lethal to numerous organisms in offshore and nearshore ecosystems. In addition, regulations in various jurisdictions throughout the world prohibit discharges of contaminated water or limit such discharges.
Thus, a need exists for a water treatment system usable on a vessel for treating wastewater and removing contaminants to an acceptable level allowing wastewater to be discharged overboard without causing adverse effects to the ecosystem in which the wastewater is discharged.